# Copyright 2022 Huawei Technologies Co., Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============================================================================
"""ResidualCell module."""

from mindspore import nn


class ResidualCell(nn.Cell):
    """
    Cell which implements Residual function:

    $$output = x + f(x)$$

    Args:
        cell (Cell): Cell needed to add residual block.

    Returns:
        Tensor, output tensor.

    Examples:
        >>> ops = ResidualCell(nn.Dense(3,4))
    """

    def __init__(self, cell):
        super(ResidualCell, self).__init__()
        self.cell = cell

    def construct(self, x):
        """ResidualCell construct."""
        return self.cell(x) + x
